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MALPEDIA_Win_Jssloader_Auto

autogenerated rule brought to you by yara-signator

MalwareJssloaderMalpedia signator rulesCreative Commons Attribution-ShareAlike 4.0Compiles with YARA-X
Author
Felix Bilstein - yara-signator at cocacoding dot com
Date
2026-05-04
Modified
2026-05-18
Score / Quality
75 / 75

What this rule detects

autogenerated rule brought to you by yara-signator

Associated malware family: Jssloader.

It defines 10 patterns (0 text, 10 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

win-jssloader-auto.yarCreative Commons Attribution-ShareAlike 4.0
rule MALPEDIA_Win_Jssloader_Auto : FILE
{
	meta:
		description = "autogenerated rule brought to you by yara-signator"
		author = "Felix Bilstein - yara-signator at cocacoding dot com"
		id = "c2dfb866-307f-54fc-a93b-1459534d3593"
		date = "2026-05-04"
		modified = "2026-05-18"
		reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.jssloader"
		source_url = "https://github.com/malpedia/signator-rules//blob/c901f97b7df03e41917da74c2a84b04c227316c2/rules/win.jssloader_auto.yar#L1-L122"
		license_url = "N/A"
		logic_hash = "0c3f13c685066a735b5bd23ece29387da4f47270047d27c85f2f68d54bf6b421"
		score = 75
		quality = 75
		tags = "FILE"
		version = "1"
		tool = "yara-signator v0.6.0"
		signator_config = "callsandjumps;datarefs;binvalue"
		malpedia_rule_date = "20260422"
		malpedia_hash = "a182e35da64e6d71cb55f125c4d4225196523f14"
		malpedia_version = "20260504"
		malpedia_license = "CC BY-SA 4.0"
		malpedia_sharing = "TLP:WHITE"

	strings:
		$sequence_0 = { 83f81f 0f8703060000 51 56 e8???????? 83c408 c745d800000000 }
		$sequence_1 = { 8b4804 8d41f8 89840d70feffff 8d85dcfeffff }
		$sequence_2 = { 68???????? c78568fdffff00000000 c7856cfdffff0f000000 c68558fdffff00 e8???????? c645fc16 }
		$sequence_3 = { 64a300000000 8b4508 89859cfeffff 8985b8feffff }
		$sequence_4 = { 8d8da0feffff c785b0feffff00000000 c785b4feffff0f000000 c685a0feffff00 e8???????? 8d85a0feffff }
		$sequence_5 = { 8b45fc 8b7008 8b5004 8b08 c7400800000000 c7400400000000 }
		$sequence_6 = { 8d8d20ffffff 6a06 68???????? c78530ffffff00000000 c78534ffffff0f000000 c68520ffffff00 e8???????? }
		$sequence_7 = { 7408 8817 47 897de8 }
		$sequence_8 = { 51 6a01 6a00 68???????? 52 ff15???????? 8d4b04 }
		$sequence_9 = { 8b04bd701d4400 834c0318ff 33c0 eb16 e8???????? c70009000000 e8???????? }

	condition:
		7 of them and filesize < 581632
}

Strings (10 patterns)

IdentifierTypeValueModifiers
$sequence_0hex{ 83f81f 0f8703060000 51 56 e8???????? 83c408 c745d800000000 }
$sequence_1hex{ 8b4804 8d41f8 89840d70feffff 8d85dcfeffff }
$sequence_2hex{ 68???????? c78568fdffff00000000 c7856cfdffff0f000000 c68558fdffff00 e8???????? c645fc16 }
$sequence_3hex{ 64a300000000 8b4508 89859cfeffff 8985b8feffff }
$sequence_4hex{ 8d8da0feffff c785b0feffff00000000 c785b4feffff0f000000 c685a0feffff00 e8???????? 8d85a0feffff }
$sequence_5hex{ 8b45fc 8b7008 8b5004 8b08 c7400800000000 c7400400000000 }
$sequence_6hex{ 8d8d20ffffff 6a06 68???????? c78530ffffff00000000 c78534ffffff0f000000 c68520ffffff00 e8???????? }
$sequence_7hex{ 7408 8817 47 897de8 }
$sequence_8hex{ 51 6a01 6a00 68???????? 52 ff15???????? 8d4b04 }
$sequence_9hex{ 8b04bd701d4400 834c0318ff 33c0 eb16 e8???????? c70009000000 e8???????? }

Condition

7 of them and filesize < 581632

In plain words (Heuristic)

  • The file must be smaller than 581632 (a cheap guard that skips large files).
  • At least 7 patterns in the rule must match.

Test this rule in your browser

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References

Licence & attribution

Author: Felix Bilstein - yara-signator at cocacoding dot com

Source repository: Malpedia signator rules @ c901f97b7d

Licence: Creative Commons Attribution-ShareAlike 4.0 (repository licence)

Original rule

Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.

Rule id: c2dfb866-307f-54fc-a93b-1459534d3593

Metadata

version1
toolyara-signator v0.6.0
signator_configcallsandjumps;datarefs;binvalue
malpedia_rule_date20260422
malpedia_hasha182e35da64e6d71cb55f125c4d4225196523f14
malpedia_version20260504
malpedia_licenseCC BY-SA 4.0
malpedia_sharingTLP:WHITE

Tags:FILE

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